Abstract:

Different lining structures have been used in challenging underground projects around the world for decades but in Finland these lining structures are rare. Despite the unreliable outcome of pre-grouting, it is regarded as the only cost-effective method for waterproofing an underground facility. The new sprayable lining solutions might change the situation though.

At the center of the new sprayable lining solutions are the spray-applied waterproofing membranes. This thesis studied two materials; a sprayable waterproofing membrane TamSeal 800 and a waterproof thin support liner TamCrete SSL. Both materials are products of Normet Oy. The main objective of the thesis was to define the waterproofing characteristics of these materials. These characteristics were studied with field tests.

The main results were that TamSeal 800 and TamCrete SSL are both powerful waterproofing layers but the applying phase is crucial. Preparatory work as well as every other working phase must be carried out carefully. For example active water ingresses should be removed beforehand. TamSeal 800 had much longer drying times than was expected. All in all, it was established that the new sprayed linings do offer interesting opportunities even though they do not completely remove the need for pre-grouting. Pre-grouting continues to be important especially if groundwater level needs to be controlled.

The future projects with strict sealing requirements should test waterproof linings with spray-on membranes because of the potential benefits achievable with these lining structures. It is recommended that the future projects would first pre-grout the facility and afterwards build the lining structure. By studying these pilot projects, it is possible to find out the overall cost-effectiveness of these linings.

TamCrete SSL is a promising product but the good waterproofing characteristics seem to be secondary in comparison with the strength properties. Before larger applications, the exact strength properties should be determined. The future researches should also determine if TamCrete SSL can replace sprayed concrete as a permanent support structure since this feature determines the full extent of applications for this product.Verhoilurakenteita on käytetty haastavissa maanalaisissa tiloissa eri puolilla maailmaa vuosikymmeniä, mutta Suomessa tämä on harvinaista. Esi-injektointia pidetään lopputuloksen epävarmuudesta huolimatta usein ainoana kustannustehokkaana vesieristysratkaiuna. Uudentyyppisten verhoilurakenteiden yleistyminen voi kuitenkin muuttaa tilannetta.